The invention relates to a boundary-layer-influencing aerodynamic part, an aircraft component equipped with such a boundary-layer-influencing aerodynamic part and a method for producing the same.
The suction and ejection of air in the region of a boundary layer flow on an aerodynamic component are known methods of influencing the boundary layer. These methods are used to avoid or delay a flow breakdown along a flow surface of the aerodynamic component, i.e., a transition from a laminar to a turbulent flow, in order to improve aerodynamic properties, in particular a flow resistance or lift coefficient, of the aerodynamic component.
Tangential suction and ejection or slot suction and ejection are currently known methods for influencing the boundary layer flow on an outer skin of an aircraft. For example, GB 25 22 531 A discloses an aircraft wing, the outer skin of which is provided with a slot for ejecting air in the direction of a boundary layer flow along the outer skin. One implementation of this method is found on the Lockheed F-104 “Starfighter” aircraft, which has an outlet slot on an upper side of the landing flaps for ejecting air. Bleed air taken from an engine is supplied to the outlet slot, due to which additionally accelerated air is ejected into the boundary layer flow along the landing flaps in such a way that stabilization of the laminar boundary air flow is achieved. The maximum lift coefficient of the landing flaps is increased by this effect, due to which the landing speed of the aircraft can be reduced.
Furthermore, the method of continuous suction and ejection of air along a porous external surface of an aerodynamic component is known from the prior art. DE 44 14 205 A1 describes an arrangement for boundary layer suction along an outer skin of an aircraft around which air flows. The arrangement comprises a multilayer construction through which air can flow, with a porous carrier layer, which is arranged on a supporting structure and to which a layer of microfiber fabric is applied. A similar arrangement is known from U.S. Pat. No. 5,618,363 A, in which an outer skin of an aircraft around which air flows is formed in some sections with a porous, carbon-fiber-reinforced thermoplastic layer, through which layer air can flow.
U.S. Pat. No. 7,275,720 B2 further discloses an arrangement for the continuous ejection of cooling air on an external surface of a spacecraft. The arrangement comprises a carrier structure, to which a porous ceramic foam layer is applied, through which cooling air can flow and which guides the cooling air along the carrier structure in the direction of a semi-permeable cover layer. The semi-permeable cover layer comprises a ceramic composite material which is applied to the ceramic foam layer by means of an adhesive. On re-entry of the spacecraft into the earth's atmosphere, cooling air is ejected along the ceramic foam layer from the semi-permeable cover layer to cool the outer skin of the spacecraft.
A commercial application of such methods for influencing the boundary layer to aerodynamic components, such as in passenger airliners, for example, does not currently take place.